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Troubleshooting Walk-Through

Upper electric element port

We get so many questions about electric water heaters, and find ourselves answering similar questions so often that we decided it would be good to have a little troubleshooting guide just for them. However, take a quick look at the other questions below that don't deal specifically with "no hot water" problems.

Do be aware that electricity is dangerous and that you can kill yourself pretty easily if you don't know what you're doing. Lots of folks come to The Tank because they don't want to hire an electrician or plumber to fix a problem, but saving money is meaningless if you lose your life in the process.

The usual complaint is, suddenly there is no hot water. That usually means the high limit has tripped. The first thing to do always, is to turn off the power, remove the cover from the upper element port, take out the insulation, remove the cover to the element assembly, if needed, and press the red reset button, circled at right, since its red doesn't show up too well here. If you don't hear the button click or don't have power after pressing it, then the high limit is bad. If this is so, use your nose. Can you smell anything burned? Are there scorch marks or signs of water? If so, that's what caused the problem. Also, if the high limit didn't click when you pressed it, the limit might be working OK and not be the problem. A volt-ohm meter can tell.

If it's wet inside the compartment, it may be a sign the water heater is on its last legs. Water can also cause the spring clip that holds the thermostat against the tank to rust. If the clip is damaged, the thermostat won't read properly and may cause the high limit to trip.

Also, every time you inspect an element port, put everything back the way you found it. There is a reason for the cover and insulation.

Often when a high limit trips, it's a symptom of another problem. We're going to take you on a tour as you follow the electricity down from the breaker box, eliminating suspects as we go. Remember, any time you open element ports, you should turn off the power.

You'll need a multimeter for this. Since we're fond of analog meters, we'll be using the terms associated with their use. If you are unfamiliar with multimeters and 240 volts, DON'T ATTEMPT THIS. HIRE A PLUMBER OR ELECTRICIAN.

First check the power at the circuit breaker to make sure the breaker isn't bad. Also make sure there are two 30-amp breakers running at 230 volts. If something less than that is being used, that right there is a problem.

Then open the upper element port and check the screws above the high limit, then under the high limit. If there is power at the circuit breaker, but not at the high limit, check power at the junction box on top of the heater

Next place to check is at the screw terminals on the upper element (see picture, yellow circle) after making sure the upper thermostat is turned up high. If you check, you should have about 240 volts at the terminals on the upper element. If not, then either the thermostat is bad or you need a wiring diagram to ensure that all the wires go the right place.

If you have power to the upper element, but the element isn't heating, check it with an ohm meter. Turn power to the heater off, and use the meter to double-check that it's really off, then undo one wire from the element and bend it out of the way.

Set your meter in the ohms times one or two scale. Test between the two screws on the element. If the needle moves most of the way over, it's good. Then you switch to ohms times 1,000 scale and put the lead on one screw of the element and one on the flange of the element to ground to test for leaks to ground.

Check first one screw, then the other. If you get any reading at all, there is a leak to ground and the element needs to be replaced.

At this point, you know you have power to the upper element and whether the element is good or bad. If it's good, you're getting a half tank of hot water. If there is insufficient hot water, then the next thing to do is check the lower element.

Check in the same way as the upper element for 240. It's normal to have 120 at an element when it's off. If the thermostat is working correctly, you should find about 240 at the lower element between the two terminals. Again check for leaks to ground. If you don't have power to the lower element, check at the lower thermostat or follow the wires down to the lower element, one directly one to the thermostat.

If you check between those two wires, you should have 240 volts assuming the bottom of the tank is cold. If not, then the upper thermostat is not switching correctly and needs to be replaced. If you find you don't have 240 from the other side of the thermostat and the wire on the element, then the lower thermostat is bad and not switching. If you find you have 240 at element screws but it's not heating, then the element must be bad, but you should already have tested for that.

Other issues that can degrade the amount of hot water a tank produces include cross connections and broken dip tubes. Follow the links to read more about those.


Overheating Fuse Box

Q: I have a two-fuse fuse box supplying power to a 60 gallon Giant electric water heater. Yesterday, the right fuse (30amp) became so hot it partially blackened the socket into which it is screwed along with producing a burnt Bakelite type of smell. I unscrewed the fuse and it was extremely hot (although surprisingly it did not blow). I checked the elements for continuity and shorts and both appear good. What could be overheating the fuse so badly?

A: Hello: This is unsafe! All connections in the fuse-box need to be looked at as there is likely a loose one that's shorting. I'd replace the fuses as well and better yet think about breakers. There are breakers made to fit the screw in type fuse holders. Sorry to say it but you need to turn off the heater until the box is looked at.. -- Larry

Q1: I checked the fuse box (it's only two years old) and everything is OK. The white wire from the entry panel leading to the hot fuse on the right side of the fuse box is blackened where it is secured at the terminal. Interestingly, a time delay 30 amp fuse does not blow, just gets very hot. A normal 30 amp fuse does blow after 3-4 minutes. I've checked both elements for shorts and they appear fine. There is some small continuity between the two left terminals of the upper thermostat. Could this be causing the right side (white wire) to be drawing more current?

A1: Hello: Is the heater running at about 240 volts? If so, there should be only two black (hot) wires and no white (neutral) involved. If the fuse/breaker overheated that much, replace it. Check for continuity/leaks to ground in the heater. That's done by disconnecting wires and checking at each screw terminal and at ground. Put the meter in ohms times 1000 or some similar sensitive range. I'd treat this like you were going to a job to troubleshoot and assume nothing about the condition of the fuse box or wiring. If it were right, there could not be overheating in the box. Do let us know what you find. -- Larry

A2: Larry, If WH was wired using 2 wire (with ground) nonmetalic sheathed cable, there very well could be a white wire. Electrician should have taped the white wire black but I see a lot of cases where it was not. -- David

A3: Hello David: I once ran across a job where the green wire was hot and the red was neutral :shock: It's sort of like breaking the speed limit while driving on the wrong side of the road, backwards. Carrying a meter is good. -- Larry

Q2: Thanks Larry. I tested both elements and there are no shorts -- but they are 10 years old and maybe calcium build-up is making them run hot. I figure I'll change both elements and maybe the two thermostats to boot and whatever caused the fuse box to overheat should go away.

A4: Hello Jack: It sounds like the leaky element has developed a hole through the copper sheath that's in water. That would make it short out. I'd check with a meter, set to one ohm, between each screw on the element and ground, (the tank) to see if there is continuity. Then check again at 1000 ohms if the meter had shown no reading.

If you find any leak to ground, replace the element. When you install the new one, put two or three turns of teflon tape on the element threads. This is in addition to the new gasket. It will allow you to correctly tighten it and make it easier to remove in future. Do make sure the fitting is quite clean before putting in the new element.

The leaking water likely caused a thermostat to malfunction too. The problem is knowing which thermostat. Look for any moisture or evidence of arcing at both thermostats. Replace if you find either of these. I've left out steps which anyone familiar with electricity knows. Please don't guess with electricity, get help if you need it. -- Larry (9/23/04)

Q2: Thanks Larry. I tested both elements and there are no shorts - but they are 10 years old and maybe calcium build up is making them run hot. I figure I'll change both elements and maybe the two thermostats to boot and whatever caused the fuse box to overheat should go away.

A5: A 4500 watt WH element is 12.8 ohms whether it is new or 20 years old, whether it is clean or scaled up. The scale will act as an insulating layer and cause the centerline temperature to increase in order to drive the heat flux through the scale. But nothing about the WH will cause the fuse box to over heat. You did not specify your element size. Normally WHs operate one element at a time. If your upper thermostat malfunctioned and you had both elements energized simultaneously and you have 3800 watt elements and voltage was 230 instead of 240 then both elements operating together would draw 30.34 amps. If you change anything, the top thermostat is most suspect. But I'd prove it with a meter before I started changing parts wholesale. -- David

Q3 : My tank has two 4500W elements and measured voltage is 234 so you could have a point. I tested the upper thermostat with an ohm meter by placing a lead on each of the two left-hand terminals as instructed by someone on this site. There was some continuity which according to the instructions would indicate the thermostat should be changed out. Do you think the thermostat could be malfunctioning intermittently? I tested it yesterday and it seemed to be functioning properly (sending 230 volts to the upper element and about 48 volts to the lower, then switching to the lower with about 230 volts once upper tank water temp reached set level).

A6: When thermostats misbehave they usually continue to misbehave. Your results seem to indicate a good thermostat. The top thermostat sends power to either the top element or the bottom thermostat. Of course the other (non-thermostat) side of each element is always hot. -- David

A7 : You say a normal fast-acting 30 amp fuse blows in 3-4 minutes. If it's really a 30 amp fuse, that would argue that something is indeed drawing a too much, as a single 4,500w element at 230 volts should only draw about 20 amps. So either you have another load also running off that fuse (trace out the wiring) or somehow the water heater is energizing both elements at once.

Any chance you tested with a 20 amp fuse by mistake? (Somebody help out - any chance those element draw a lot until the get hot? Some heating materials have what is called high temperature coefficients, meaning they have a different resistance when cold (simple tungsten light bulbs are a great example). Seems unlikely to fully explain your problem, though, as the localized damage to the fuse-box tells a different story. See next paragraph.

Assuming the heater wiring checks out, it is quite possible that the problem is not the water heater and it is not that something is drawing too much current (e.g. no shorts). The super hot fuse and blackening sounds like there is a poor connection in the fuse-box. That is to say, something is (or was) not tightened properly. What happens is that the poor connection doesn't conduct electricity very well and gets warm due to the current flowing through it to the heater.

Your heater draws about 20amps. If the connection to the fuse had a 0.5 ohm resistance, the current would cause 10 watts to generated at the fuse (Think a small light bulb's worth). That would cause the connection to get very warm. The heat causes local oxidation of the connection which makes it worse and you get more resistance and more heat. Eventually you end up with the wire, the fuse socket, etc getting extremely hot (but not enough to blow the fuse). While not common, it is certainly not rare.

Note, the heat damages whatever is loosely connected as well the socket/wire/etc nearby. It might have started with a fuse that wasn't screwed in tight, or a wire that wasn't securely connected to the fuse box. Any good electrician will know what to do. If you want to handle it yourself, you will need to kill the power, partially disassemble the fuse-box, and replace anything that shows signs of heat stress.

A little bit of darkened insulation of a wire is not the end of the world, but charred insulation needs addressing (replace the wire or reinsulate in a code-approved manner) AND any damaged fuse socket needs replacing. The spring contact loses its springiness and contact plating get damaged, etc. Hope this helps -- Sky_Tech

Q4: Thanks Sky_Tech, I`ll check the fuse box this weekend (the water heater is in a country home that we use only on weekends). (2/10/10)


Electric Thermostat Replacement

Q: Can you help me find a better thermostat replacement than the Apcom thermastats that Sears sells? I've had the 66-gallon Kenmore Power Miser 8+ , Model #153.318660 for five years now and replaced the lower therm last year. Now the upper is shot. I've heard that these Apcom thermastats stink ( and my experience has proved it). Any idea where I can find a better thermostat that will fit?

A: Try Robertshaw. If the hardware store doesn't have them, try a plumbing wholesaler. -- Larry (1995-2000)


Burned-Out Element

Q: I have a 40-gallon electric water heater that is 18 years old. It has only been drained once or twice that I am aware of in the past by professionals. I had hot water from the showers and sinks yesterday, but as of this morning, I am getting nothing but cold water through the faucets. I am a female who lives with her teen-age boys. Could you possibly give us instructions on how to drain the tank, replace the thermostat, or tell me whether or not I need a brand new tank? Thank you.

A: I apologize for not responding sooner. I was out of town and just returned today. I do not advise you to try to work on your water heater yourself if you are unfamiliar with such things, which seems likely from what you've told me. The reason for that is that 220-volt can be dangerous. Eighteen years is good life for a water heater, but your problem doesn't necessarily mean yours needs to be replaced. By now, you may already have dealt with your problem, since two or three days is a long time to endure cold water, but if you haven't, the first thing I'd do is find the breaker box, locate the breaker for the water heater and reset it. That might solve your problem, or it might solve it briefly. If it's the latter, ask the plumber to check the high-limit switch and thefrmostats. Otherwise, there's a good chance your lower element has burned out and needs to be replaced. -- Randy (1995-2000)


Electric Element Problems

Q: Found you through Yahoo. Could you please answer my question? Have twice replaced the 240-volt single element on a 10-year-old State 52-gallon heater which is rated for 5500 watts. Because the first element I removed was rated 4500 watts, I replaced it with a basic cheap 4500-watt one. That gave up the ghost and I replaced it with another of the same. This second one repeatedly pops the reset button on the heater (I have never known it to pop the circuit breakers in the house panel). My question is: why would a lower-watt-rated element burn out or pop the tank reset? I can understand that it would take longer to heat the thing? Would a better-quality 5500-watt element be apt to keep running? I know this is an iffy question but thought your knowledge would help make a decision on the type of element or whether to skip all that and install a new heater. Thanks.

A: Sediment build-up is burning out elements and possibly overheating the high limit, causing it to pop. Would suggest cleaning sediment from tank and using a low-watt-density element to reduce sediment build-up. Also check your anode, if you can, to see if there's anything left of it. 4500 or 5500 watts should not make any difference which would be noticed as far as overheating goes. -- Larry (1995-2000)


Q: We have a State electric water heater model 510D that is overheating, which in turn, is causing the high-limit temperature cutoff to shut off power to the heating elements. The first indication before this occurs is that the temperature of the hot water outlet pipe is extremely hot even though the thermostat dial is set to minimum on both the upper and lower thermostat. With both thermostat dials set to minimum, I checked the upper thermostat (3 terminal) two left terminals and measured infinite resistance. The upper left and lower right terminal measured 0 ohms and when I adjusted the thermostat dial to maximum these measurements didn't change. I also measured the lower thermostat (2 terminal) and measured infinite resistance in either dial positions (minimum or maximum). Do you have any suggestions on what else I should try? For now, I've been just resetting the cutoff button. Thanks for listening.

A: With this dual element heater, when the heater is very hot, turn off power and feel the tank itself down at the lower element. If the tank is quite hot that tells you the lower element is doing the overheating. That means the lower thermostat isn't working and needs replacement. If the tank is hot only from the upper element up, then the upper thermostat is suspect. -- Larry (1995-2000)


Q: After installing a new electric water heater and filling with water. should'nt both elements come on initially since the tank is full of cold water. I dont understand how this works.

A: Modern electric heaters are wired for "non-simultaneous operation". What this means is that when filled with cold water, the upper element comes on first. Once the upper part of the tank is hot, power is switched to the lower element, which heats the majority of the water. The purpose of the upper element is to provide quicker hot water and perhaps to give a little redundancy so that one doesn't completely run out of hot water should the lower element fail. If both elements did come on at the same time, larger breakers and wiring would be needed. In addition, electrical consumption would be harder for utilities to manage. Some new tanks do come with only one element at the bottom, which simplifies the heater but also makes it more likely to leave you cold. -- Larry (9/27/04)


Keeps Blowing a Fuse

Q: My hot water heater is on a 15 amp fuse. The hot water heater is only about 2 years old. It worked perfectly up until recently. Now it keeps blowing the fuse. If I change the fuse it works to heat it back up and then blows again. One time I put in a breaker fuse and it blew a couple times and I kept resetting it. Then it all of a sudden lasted for about 2 months and now it is blowing again. We did change one of the elements, not sure which. Any idea why this is happening? Actually now the fuse only lasts about 5 mins and then blows and when I try to reset the fuse it blows right away.

A: Normally, water heaters are on two, 30 amp breakers and run at 230 volts. Wire size often is #8. 15 amp breakers or fuses are much too small unless you have undersized wire. (the breaker protects the wire from overheating/causing a fire) It may be time to have an electrician take a look at your situation and make it safe. You DO NOT want to run a modern heater on undersized wire. -- Larry (11/30/04)

Circuit Breaker Keeps Tripping

Q: A few days ago I had no hot water. The curcuit wasnt tripped, and I couldnt figure the problem. I looked online and seen something about manually resetting the EOC (or something like that). I turned off the breaker, took the panel off and pushed a red button on the upper element. Then I turned the breaker back on and about 3-4 minutes later, the breaker tripped. I turned the breaker back on, and 3-4 minutes later it tripped again. While this was happening, the water heater knocked a few times. I reset the breaker again and it was fine. I had hot water and everything was cool, until today (I hate cold showers before work). The same thing has happened with me resetting the red button, the breaker tripping , etc. However, I didn't hear any knocking this time. In addition, I have noticed air in the pipes when turning on and off faucets. I don't know if I've had this problem since I've moved in, or if its rescent. Or even if it has anything to do with the heater. I don't know how old the water heater is because we just bought this house 3 months ago. This all started happening over the last weekend. Also, we have well water too, if that makes a difference.

A: It sounds like there may be a leak to ground in one of the elements. Possibly the upper one overheated if it was exposed to that air. If you search in the other topics for info on checking elements, it might help. Additionally, thermostats could be an issue. Lastly and if it keeps tripping, I'd also be ready to replace the circuit breaker after the heater is fixed up. The elements sound suspicious...I'd start there. -- Larry (9/27/05)


Troubleshooting an Electric Water Heater

Q: I have electric GE Smart water heater which is around 5 years old (80 gals). Last night it stopped working. I checked the braker it is good. Is there a reset botton on the heater? Any thing I can do to fix it. I am somewhat good with fixing things.

A: Hello: I can tell you how to troubleshoot electric heaters in general. GE is actually Rheem. I don't know how smart it may be. You'll need a volt-ohm meter and you'll need a degree of experience around 240 volts. Please don't do the work yourself if you're not conversant with 240 VAC. So... Did you notice that the water was hotter before it went cold? If so, there is a high limit switch under the upper panel, that needs pushing. If you hear it click, than you've reset it. Power should be off any time a cover is removed.

Check with your meter before touching anything, even if you think the breakers are off. Sometimes the wrong breakers are off! Next question is why did it overheat? Do you see any moisture around the elements... or heavy rusting? Water and thermostats do not mix. Any darkened areas around thermostats suggest arcing, which is the end of that thermostat.

Elements could be bad or going bad too, but before my droning on, it would be best for you to turn off the power, remove both covers and let us know what you see there. That will give clues on how to proceed if what I've already written doesn't cover it. Hope that helps. -- Larry

Q1: This problem seems similar to mine. (GE electric heater, 3 years old) A few days ago, the hot water suddenly started out coming out scalding hot, then it went lukewarm. Upon checking, I noticed that the breaker was tripping. I opened up the top panel and hit the reset switch. The switch on the thermostat itself hasn't been tripping again, but the circuit breaker is.

Also, Right around the heating element gasket, a small amount of water will form a drip or two when the circuit breaker is switched back on, (I'm wondering if this is normal) and I get some hot water for awhile, but invariably, the circuit trips again. Would a bad element be the cause of this tripping, and do you think replacing it will solve the problem? If I replace the element, should I also replace the thermostat?

A1: Hello Jack: It sounds like the leaky element has developed a hole through the copper sheath that's in water. That would make it short out. I'd check with a meter, set to one ohm, between each screw on the element and ground, (the tank) to see if there is continuity. Then check again at 1000 ohms if the meter had shown no reading.

If you find any leak to ground, replace the element. When you install the new one, put two or three turns of teflon tape on the element threads. This is in addition to the new gasket. It will allow you to correctly tighten it and make it easier to remove in future. Do make sure the fitting is quite clean before putting in the new element.

The leaking water likely caused a thermostat to malfunction too. The problem is knowing which thermostat. Look for any moisture or evidence of arcing at both thermostats. Replace if you find either of these. I've left out steps which anyone familiar with electricity knows. Please don't guess with electricity, get help if you need it. -- Larry (9/23/04)

 

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